Electronic and magnetic properties of adsorbed H2 on graphene with atomic defects: Ab initio study

• H2 is not dissociated on doped graphene with B, Fe, Co and N.
• The lower adsorption energies are obtained for the alkali atoms Li, Na and Ca.
• The conducting character is high for doped graphene with Cr, Mn and Fe.
• Graphene, graphene-Si and H2/graphene-Si have a zero-band gap character.
• H2/doped graphene systems are not magnetic.

We have performed ab initio calculations based on the pseudo-potential density functional theory to investigate the structural, electronic and magnetic properties of H2 on graphene with and without addition of the atomic defect. The spin-polarized generalized gradient approximation was added to the exchange-correlation energy functional. The atomic defects were H, Li, Be, B, N, O, Na, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Co, Ni and Cu. The electronic properties were analyzed in terms of the density of states. We have found that doped-graphene systems with and without H2 have different equilibrium geometries, densities of states and magnetic properties. Also, drastic distortions were observed around the atomic defects and new behaviors appear in the vicinity of the Fermi levels. The H2 adsorption has altered the insulating/conducting as well as the paramagnetic/ferromagnetic characters of the doped-graphene structures. The obtained results have revealed that the addition of the atomic defects to graphene is interesting and promising way in improving the adsorption process of H2 as well as in altering the electronic and magnetic properties.